avr: introduced network module

this will be the base module for network modules.

avr/modules/network/main.asm

@@ -0,0 +1,82 @@
+; ***************************************************************************
+; copyright   : (C) 2025 by Martin Preuss
+; email       : martin@libchipcard.de
+;
+; ***************************************************************************
+; * This file is part of the project "AqHome".                              *
+; * Please see toplevel file COPYING of that project for license details.   *
+; ***************************************************************************
+
+
+.cseg
+
+
+
+; ---------------------------------------------------------------------------
+; @routine NET_Init
+;
+; Initializes buffers.
+;
+; @clobbers R16, R17, X
+
+NET_Init:
+  ldi xh, HIGH(networkDataBegin)
+  ldi xl, LOW(networkDataBegin)
+  clr r16
+  ldi r17, (networkDataEnd-networkDataBegin)
+  rcall Utils_FillSram                        ; (R17, X)
+
+  rcall NET_Buffer_Init                       ; (R16, R17, X)
+
+  ldi r16, NET_MSGNUMINBUF_SIZE
+  ldi yl, LOW(netRingBufferMsgNumIn)
+  ldi yh, HIGH(netRingBufferMsgNumIn)
+  rcall RingBufferY_Init                        ; (R17)
+
+  sec
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine NET_AddIncomingMsgNum @global
+;
+; @return CFLAG on success, cleared on error
+; @param R16 buffer number of the next incoming message
+; @clobbers R17, R18, X
+
+NET_AddIncomingMsgNum:
+  push yl
+    push yh
+      ldi yl, LOW(netRingBufferMsgNumIn)
+      ldi yh, HIGH(netRingBufferMsgNumIn)
+      rcall RingBufferY_WriteByteGuarded        ; R17, R18, X
+    pop yh
+  pop yl
+  ret
+; @end
+
+
+
+; ---------------------------------------------------------------------------
+; @routine NET_GetNextIncomingMsgNum @global
+;
+; @return CFLAG on success, cleared on error
+; @return R16 buffer number of the next incoming message
+; @param Y pointer to start of interface data
+; @clobbers R17, R18, X
+
+NET_GetNextIncomingMsgNum:
+  push yl
+    push yh
+      ldi yl, LOW(netRingBufferMsgNumIn)
+      ldi yh, HIGH(netRingBufferMsgNumIn)
+      rcall RingBufferY_ReadByteGuarded         ; R17, R18, X
+    pop yh
+  pop yl
+  ret
+; @end
+
+
+